Cook the rotini as directed on package.
Roast/or grill the zucchini, eggplant, pepper, and tomato (optional) with 1/2 of the thyme, salt, and olive oil, reserving the rest for the dressing.
Rinse, drain, and cool the pasta.
When the roasted veggies are done set aside to cool.
Cut up the cucumber and red onion.
Add them to the pasta, do not mix in yet.
Add the rest of the olive oil, thyme, and salt, along with the garlic powder, onion powder, celery salt, red pepper flake, and vinegar.
Add in the roasted vegetables and olives, mix lightly.
Add the feta cheese not mixing but folding it into the salad.
Taste and adjust if you want more salt, vinegar, oil or heat.